3D-Printed Synthetic Hydroxyapatite Scaffold With In Silico Optimized Macrostructure Enhances Bone Formation In Vivo

3D printing technologies are a promising approach to treat intra-oral bone defects, especially those with poor regenerative potential. However, there is a lack of evidence regarding the impact of internal design specifications on the bone regenerative potential. Here, an in silico approach to optimize the internal design of calcium phosphate-based scaffolds for bone regeneration is proposed. Based on an in silico model of neotissue formation, a gyroid 3D-printed scaffold is designed and manufactured using UV stereolithography of bioceramic materials. An orthogonal lattice structure 3D-printed scaffold and a particulate xenograft are used as control groups. The scaffolds are implanted subperiosteally under a shell on rat calvarium for 4 or 8 weeks and bone neoformation performances are investigated by nanofocus computed tomography and decalcified histology. After 8 weeks, the gyroid group is associated with a higher ingrowth potential of the bone and is characterized by signs of osteoinduction (newly formed bone islands). The bone to material contact is similar between the gyroid and the particulate groups. The present results reinforce this in silico modeling strategy to design calcium phosphate-based 3D scaffolds and the gyroid experimental internal architecture seems to be highly promising for intra-oral bone regeneration applications.